Built environment microbiota associated with occurrence of Listeria monocytogenes in tree fruit processing facilities
Open Access
- Author:
- Tan, Xiaoqing
- Graduate Program:
- Food Science
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- May 10, 2019
- Committee Members:
- Luke F Laborde, Thesis Advisor/Co-Advisor
Jasna Kovac, Thesis Advisor/Co-Advisor
Edward G Dudley, Committee Member - Keywords:
- Listeria monocytogenes
microbiota
mycobiota
fruit
built environment
Listeria monocytogenes
microbiota
mycobiota
fruit
built-environment - Abstract:
- High mortality rate associated with foodborne pathogen Listeria monocytogenes has raised food safety concerns. Recent outbreak and recalls due to L. monocytogenes contamination of apples or apple products demonstrated the need for improved pathogen control in the apple supply chain. The purpose of this study was to elucidate the potential association between the composition of the native microbiota and the occurrence of foodborne pathogen L. monocytogenes in apple processing facilities, which have been identified in the past as potential sources of persisting L. monocytogenes contamination. L. monocytogenes was detected in environmental sponge swabs by following the FDA Bacterial Analytic Manuel (BAM) protocol for enrichment of Listeria monocytogenes. The facility microbial and fungal compositions were characterized through 16S rRNA and ITS2 amplicon sequencing. Analysis of 117 samples from the three investigated apple packing facilities (i.e., F1, F2 and F3) showed that facility F2 had a significantly higher L. monocytogenes occurrence compared to F1 and F3 (P < 0.01). Furthermore, facility F2 had distinct microbiomes compared to facilities F1 and F3. The mean microbial and fungal alpha diversity determined using Shannon index were both significantly different (P < 0.01) in F2, compared to F1 and F3. Higher relative abundance of Pseudomonadaceae was observed in facility F2 which had higher occurrence of L. monocytogenes. Furthermore, fungal family Dipodascaceae was found significantly higher in facility F2 (P < 0.01). Our results show that occurrence of foodborne pathogen L. monocytogenes may be associated with microbiome composition in apple packinghouses. These results provide a data baseline needed for further in-depth investigation of microbial interactions between non-pathogenic and pathogenic microorganisms found in food processing environments that may lead to optimized pathogen control strategies.